Alcohol-impaired driving results in thousands of deaths and hundreds of thousands of injuries in the United States each year. In addition, the societal costs of these consequences exceed $129 billion each year. The substantial progress made between 1982 and 1997 in reducing the fatal consequences of impaired driving has stalled for the past 15 years. Impaired-driving legislation adopted in the states has played a key role in the reductions experienced in the 1980s and 1990s. Setting illegal per se limits on the blood alcohol concentration (BAC) for driving and the adoption of administrative license revocation or suspension sanctions for drivers arrested for driving while intoxicated have been shown to be effective as general deterrents to driving after drinking alcohol. It is currently illeal, per se, for anyone aged 21 or older to operate a motor vehicle with a BAC of .08 g/dL (grams per deciliter) or greater in all states and the District of Columbia (DC). One way to resume progress in reducing impaired-driving fatalities is to lower the illegal BAC limit for driving from .08 g/dL to .05 g/dL. The illegal limit is .05 BAC in numerous countries around the world, and several international studies indicate that lowering the illegal per se limit from .08 to .05 g/dL BAC also reduces alcohol-related fatalities. Most of those international studies have been obtained, and for the remaining reports, a comprehensive literature search will be conducted. A meta-analysis of the qualified studies will be conducted to estimate the overall effectiveness of reducing the BAC limit from .08 to .05 if it is implemented in the United States. Several studies have been conducted on the implementation and effectiveness of .08 BAC laws in individual and groups of states; however, no single study has covered all 50 states and DC. This study will fill that gap by determining the overall effectiveness obtained by reducing the illegal per se BAC limit for driving from .10 g/dL to .08 g/dL in all 50 states and DC. To accomplish this, a consistent outcome measuredrinking drivers in fatal crashes as a ratio to nondrinking drivers in fatal crashesand an identical methodologytimeseries ARIMA analysiswill be used to estimate the lives saved due to the adoption of .08 BAC in all the states and DC up through 2011. Total lives saved since 1983 when the first two .08 BAC per se laws went into effect will be estimated. The results from this study will be integrated and a weighted result of the effectiveness of lowering the BAC to .05 in each state and the United States as a whole will be developed. Ultimately, this study will help state policy makers gain a better understanding of the benefits of lowering the illegal BAC limit to .05 g/dL, based on its proven effectiveness both in the United States and abroad.